How to Detect Leaks​

It is usually not clear at first glance where the leak can be found. In question are heating, water, and drainage pipes or leaks on the building envelope such as in foundations, earth-bound components, flat roofs or thermal insulation. The use of modern methods allows experienced measuring technicians to locate leaks quickly, reducing search times and costs many times over.

The different procedures are often used in combination since depending on local circumstances and damage, the use of multiple procedures may be required. Non-destructive leak detection methods are particularly suitable for leaks in heating, water, and drainage pipes.

1. How to detect leaks on a water pipe and other lines

Even a small leak in the water pipe can cause enormous damage - from mildew to damp walls to heavily damaged building materials. The causes are many and varied - corrosion, frost, material and manufacturing defects, misalignment or material fatigue may be responsible for the leak. To pinpoint the leak, professional leak detection companies such as SANAG use non-destructive leak detection methods:

humidity measurement

Electro-acoustic method

ultrasonic methods

tracer gas

UV staining

Infrared thermography technique

Computer correlation

endoscopic procedures

2. Leak detection flat roof

Mechanical influences, rain, hail, snow, and solar radiation increase the roof area. The consequences are damage caused by leaks and moisture, which should be remedied as quickly as possible. Because the flat roof is leaking, the renovation effort can quickly become very expensive.

Basically, not only the leak detection is important in the renovation of a flat roof, but also a comprehensive damage analysis or building inspection, which subsequently forms the basis of the necessary measures for water damage restoration :

Inspection of roof structures, rainwater drains, and supply linesSo that the roof structure remains intact and cost-intensive remedial measures are not even necessary, it is advisable to carry out a preventive leak detection at regular intervals in the case of a flat roof.

3. Leak detection underfloor heating

The process of infrared thermography is the method of choice for leak detection in underfloor heating systems. Since hot water pipes emit heat radiation, leaking liquids cause temperature changes in insulation or masonry. A special infrared camera makes this temperature change visible and allows the exact local determination of the leak.

How do the leak detection methods work?

Finding a leak often requires the use of multiple methods. Special know-how and corresponding experience in method application are therefore required for successful leak detection.

1. Moisture measurement

The visible parts of water damage are rarely the damaged areas. With a moisture meter, you can quickly and safely make a non-destructive determination of the moisture distribution in building materials such as wood, plaster, concrete, screed, mortar, etc. In this case, the electrical resistance of building material is determined by electrodes.

The electrical resistance changes depending on the humidity of the material and thus allows conclusions about the moisture content of the building material.

2. Pressure test

In a pressure test, individual sections of the pipeline are shut off from the pipeline network and filled with compressed air. A manometer is used to monitor the air pressure inside the pipeline. If the pressure remains constant, the line is tight. If there is a pressure loss, there is a leak.

This method is used when several pipelines are close to each other and it is to be determined which of them have a leak. In order to locate the leak precisely, the tracer gas method or an electro-acoustic method can then be used.

3. Electro-acoustic method

The electro-acoustic method is a listening method that uses alternating current and high-sensitivity microphones. At a leak usually creates a noise that expands on both sides of the leak. With the contact microphone, this noise can be perceived. The closer the leak is, the higher the tone becomes. In the place with the highest tone is the leak. Since the sound propagates only to a small extent in plastic pipes, the electro-acoustic Horchverfahren makes sense primarily in metal pipes.

4. Ultrasonic measuring technology

Ultrasonic measurement is a listening method that can also detect ultrasonic waves. As with the acoustic listening method, high-sensitivity microphones are also used here, with which the leak noises can be detected. The audibility of the flow noise is increased if necessary by the use of compressed air or tracer gas, instead of water.

5. Tracer gas

If the leak can not be detected with the electro-acoustic method, the tracer gas process is usually used. The pipelines are emptied, filled with a suitable gas mixture of nitrogen and hydrogen and then closed with a slightly increased overpressure. By means of a highly sensitive sensor, the escaping gas can then be measured in the single-digit ppm range (ppm - part per million).

The gas also diffuses through relatively dense masses such as concrete, screed, and floor slips and can be accurately identified with the help of the tracer gas measuring device.

6. UV staining method

To find leaks in drains or balcony waterproofing, a UV stain is mixed with water and introduced into sewers or distributed to balcony seals. The leak can then be visualized by means of a UV lamp.

7. Infrared thermography

With the aid of an infrared thermography camera, leaks in pipes are detected by recording high-temperature radiation and temperature differences. The thermography makes use of the fact that penetrating water has a temperature difference in the environment. By measuring the surface temperature, leaks in pipes can be made very good.

8. Computer correlation

Computer Correlation is a computerized method for locating leaks. Two radio microphones pick up the leak and send it by radio to the leak calculator (correlator). Since the noise caused by the leak spreads in both directions of the line at a certain speed, resulting from the different duration of the noise to the microphones a transit time difference. From this the leakage position can be determined exactly.

9. Endoscopy

In the endoscopic procedure, rigid or flexible endoscopes are inserted through openings of 4 - 10 mm in diameter in wall or floor shafts to detect leaks. The method is mainly used for facing and cavities (sewers, drainage pipes, channels, shafts, wooden beam constructions, rooms below the bath and shower).

10. Colorant method

Colorants are usually used for leak detection if the tightness of the water-bearing plane of a flat roof is to be checked in advance. Also for the detection of drainage leaks or leak detection in underfloor heating their use makes sense.

11. Building examination

Non-destructive leak detection is not always suitable for finding leaks. This is especially true if it is water damage due to structural defects. As part of a building investigation, the location of damaged areas in the building is based on material samples, the samples are removed by drilling or mortising at several measuring points and sent to a suitable chemical laboratory for chemical analysis.

The moisture and salt values evaluated in the chemical analysis then provide detailed information on the type of damage and the necessary remedial measures such as dehumidification or wall drainage .